Figure 2. Schematic picture of the simplified muscle model.
: variable spring constant (elasticity modulus). The actual value of
is determined by the activity of the connecting motoneuron;
can be regarded as (actual) contractility of the muscle.
: coefficient of the damping produced by viscosity. The torque generated by the damping is assumed to be proportional to the contraction velocity of the muscle fibre with a constant value of
for a given muscle type.